Authors:M. I. Yoshida, V. R. Silva, P. C. C. Pinto, S. S. Sant'Anna, M. C. Silva, and C. F. Carvalho
In the aluminum industries, there are several steps involved in processing since the extraction of bauxite to obtain the final product (Al). During the development of these, various steps generated wastes. One of them, from the electrostatic filter of the calcination step of the Bayer process is a very fine black powder, rich in alumina (Al2O3) that does not meet industry specifications, and it is discarded in the industry yard. Alumina is a noble material and has high commercial value. This black powder has great prospects for recovery, recycling, and future applications. Therefore, it is important to perform characterization of tailings and to do that we have used XRD, SEM, EDS, FTIR, Raman, and thermal analysis.
Authors:C. Bertol, A. Cruz, H. Stulzer, F. Murakami, and M. Silva
Primaquine (PQ) is the drug of choice for the radical cure of Plasmodium vivax malaria, and currently being administered in solid dosage form. In this study, the compatibility studies were carried out
using differential scanning calorimetry (DSC), thermogravimetry (TG), and fourier transformed infrared (FT-IR). Non-isothermal
and isothermal methods were employed to investigate kinetic parameters under nitrogen and air atmospheres using TG. The DSC
investigations obtained by physical mixtures showed slight alterations in the melting temperatures of PQ with some excipients.
The FT-IR confirmed the possible interactions obtained by DSC for the physical mixtures with PQ and lactose, magnesium stearate
and mannitol. The results showed that the thermal decomposition followed a zero order kinetic in both atmospheres in non-isothermal
method. The activation energy in both methods using nitrogen atmosphere was similar, and in air atmosphere the activation
Authors:P. Oliveira, L. Bernardi, F. Murakami, C. Mendes, and M. Silva
Norfloxacin (NFX) is a synthetic antibacterial drug. The development of extended release tablets improves the patients’ comfort
and compliance, resulting in lower discontinuation of the therapy; with consequently decrease in bacterial resistance. In
the present work, the thermal behavior of NFX was investigated using TG and DSC techniques. Isothermal and non-isothermal
methods were employed to determine kinetic data of decomposition process. Compatibility studies between NFX and pharmaceutical
excipients, including three hydrophilic polymers were carried out in order to develop a new formulation of NFX to obtain extended
release tablets with an approved quality.
Authors:A.F.S. Garcia, A.M. Garcia, S.R. Vollrath, F. Schneck, C.F.M. Silva, Í.J. Marchetti, and J.P. Vieira
Food partitioning among coexisting species in different habitats remains an important research topic in trophic ecology. In this work, we combined carbon and nitrogen stable isotope ratios and stomach content analyses to investigate differences in diet and niche overlap of two congeneric juvenile mullet species (Mugil curema and Mugil liza) coexisting in a marine surf-zone and an estuarine zone in southern Brazil (29oS). These habitats have contrasting levels of food availability, especially in terms of prey diversity, with higher microalgae diversity in the estuary than in the marine surf-zone. In these contrasting conditions, we predicted that both mullet species will have (a) higher niche overlap and smaller niche breadth at the marine surf-zone due to the common exploration of highly abundant surf-zone diatoms and (b) lower niche overlap and higher niche breadth inside the estuary due to selective feeding on more diverse food resources. Isotope niche areas (measured as standard ellipse areas) were higher in the estuary (6.10 and 6.18) than in the marine surf-zone (3.68 and 3.37) for both M. curema and M. liza, respectively. We observed an overlap of 52% in isotopic niches of both species in the marine surf-zone and none in the estuary. We also found contrasting patterns in the diet composition between species according to the habitat. At the marine surfzone, diatoms of the classes Bacillariophyceae and Coscinodiscophyceae dominated (> 99%) the food content of both mullet species. In contrast, green algae, cyanobacteria, dinoflagellates and flagellates comprised the diet of both species in the estuary. These results could be explained by spatial differences in food availability (especially regarding diversity of microalgae) between both habitats. At the marine site, both species explored the most abundant microalgae available (mostly the surf-zone diatom Asterionellopsis cf. guyunusae and fragments of Coscinodiscus), whereas in the estuary both species shifted their diets to explore the greater diversity of microalgae resources. Overall, our findings revealed that niche partitioning theory could not fully predict changes in breadth and overlap of food niches of estuarine dependent fish species with complex life cycles encompassing marine to estuarine systems with contrasting food availabilities.
Authors:Juliana C. Z. Conceição, Marcelo T. Moura, José C. Ferreira-Silva, Pamela Ramos-Deus, Priscila G. C. Silva, Ludymila F. Cantanhêde, Ricardo M. Chaves, Paulo F. Lima, and Marcos A. L. Oliveira
Exposure of caprine oocytes and embryos to retinoids enhances embryonic development, but the mechanisms governing this phenomenon have not been characterised. The aim of the present study was to evaluate if the incidence of apoptosis is affected by the addition of retinyl acetate (RAc) and 9-cis-retinoic acid (RA) during in vitro maturation (IVM) of caprine oocytes. Embryonic development was recorded on days 3 and 8 post-fertilisation, and apoptosis was measured by caspase activity and DNA fragmentation (TUNEL assay). Control zygotes had lower capacity to cleave and reach the blastocyst stage (24.45 ± 2.32 and 5.32 ± 0.81, respectively) than those of RAc- (29.96 ± 1.62 and 7.94 ± 0.93, respectively) and RA-treated groups (30.12 ± 1.51 and 7.36 ± 1.02, respectively). Oocytes and blastocysts positive for TUNEL assay were more frequent, respectively, in the controls (8.20 ± 0.78, 8.70 ± 1.05) than in RAc (5.60 ± 0.52, 4.80 ± 0.51) and RA (6.40 ± 0.69, 5.40 ± 0.69). Caspase activity did not differ between control oocytes (7.20 ± 0.91), RAc (6.60 ± 0.68) and RA (7.30 ± 0.67), but it was reduced in RAc- (5.05 ± 0.62) and RA-treated blastocysts (5.75 ± 0.22) compared to controls (8.35 ± 0.71). These results indicate that the addition of retinoids during IVM increases the developmental potential of goat embryos with a concomitant reduction in apoptosis rates.
Authors:J. A. S. Júnior, J. J. R. F. Cardoso, C. M. Silva, S. V. Silveira, and R. S. Amaral
Seventy nine samples, including soil and rock, were collected from the agrestic region of the State of Pernambuco, Brazil.
The activity concentrations of 238U and 226Ra in the samples were determined by gamma-spectrometry using an HPGe detector. The concentrations of 238U were 22 Bq . kg-1 to 22 kBq . kg-1. The concentrations of 226Ra were 14 Bq . kg-1 to 17 kBq . kg-1. The 238U/226Ra ratios in the soil were 0.7 to 3.4 (arithmetic mean 1.7). The radiometric data were evaluated to explain 238U and 226Ra migration in the soil and the possible consequences to the environment.